Hello,
Sorry to hear you are having issues. But, I can't reproduce it on my system. Need to know more.
1) Windows version you are running. Please use Winver.exe for full version numbers.
2) Did you reboot after the installation?
3) Please try the "Reset to automatic tabs color" and try again.
4) and if everything still fail try the purge and reinstall steps : https://forums.stardock.com/488142/groupy-support-faq#reinstalling
Just make sure to re-download the V1.8 again from your account. Reboot after the purge, re-install, reboot again. Retest and report back here.
Thanks
Basj,
Stardock Community Assistant.